Coaxial switch



COAXIAL. SWITCH 2 Sheets-Sheet l Filed OCT.. 24, 1960 Nw 0 A w av w R o@QW N uw @1,154 S1 am 1 su Oct. 13, 1964 Filed O Gt. 24, 1960 s. LAPIDUsETAL 3,153,129

coAxIAL swITcH 2 Sheets-Sheet 2 A TTO/VEYS T-type,fembodying featuresYof our invention;` i

FIG. 2 is a fragmentary view explanatoryof a detail;v

. FIG. 3 is a section takenapproximately inthe vplane of l the line 3--3of FIGA;

` 3,155,129` CAXIAL SWITCH K Solomon "Lapidus, Flushing, and MarcSheldon, New

York, NX., assignors to Bogart Manufacturing Corporation, Brooklyn, NX.,a corporation of New York Filed' 0er. 24, 196th, Ser. No. 64,347

18 Claims. (Cl. 200,-153) This invention relates to electrical switchesfor high frequency power, and more particularly to aj three-port coaxialswitch. l i Y lfhe generalobject of the invention is to improve coaxialswitches, especially T-type coaxial switches fo handling alarge amountof power. t

A more particular-.object is to provide improved'control mechanism foroperating such a switch. A st ill more specilic object is to provide amanually operable handle which turns a halfrevolution .and which is somounted thatit pointsin the direction of thebranch of the switch lwhichhas been connected ormade operable. l

Still another Objectis to provide operating mechanism which is compact,and much of which is housed inside the `coaxial conductors,withoutaffecting their electrical characteristics. Y

The switch is of the T-type and includes a lslidable element whichisrmoved axially toward one branch or the opposite branch of the T. Oneobject of the inven- United States Patent O ice Patented (Bet. 13, lgd

. to connect the common inner conductor 24 to one or the FIG .5 theslidable element 22 is in its right position, and

invention resides in the coaxial switch elements and their relation oneto another, as are hereinafter more particularly described in thefollowingspecilicaticn. VThe specication is accompanied by drawings inwhich:

FIG.` l is a section through a coaxial switch of the FIG. 4 is a sectionthrough the slidable element;

FIG. 5 is an incomplete sectionsimilar to FlGfl but showing the switchshifted to the right instead of the left branch;

FIG. 6 .is a partial plan view taken in the plane of the lineS-S of FIG.4, and drawn to reduced scale; and

' FIG. 7 shows an insulation bead for supporting the in' ner conductor.e

Referring to the drawing, the coaxial switch comprises ,v a T-shapedhousing 12 providing the hollow-outer conductor 14 of the stern orcommon portion, and thehollow outer conductors lo'and 18 of the twoaligned branches of the switch. In preferred form these outer conductorsYare cylindrical.

There is a common inner conductor 24 running through l `the outerconductor 14, and terminating at its inner end in a ring 2li which iscoaxial of thebranches lo and 18.

Thereis an inner conductor element 22 which is slidable through :thering 20. Therbranch'lohas a stationary inner conductor 2&5, and thebranch 18 has a stationary innerconductor 28.V Asusualptheinner-conductors'are preferably cylindrical and coaxial withthe outer =con ductors.` "A

'The innerend 3i) of conductor 26 and the innery end .32 of conductor28;V are located at asp'acing lfrom'the common conductor or" ring 20approximating thef'length v(it) other-of the-branch inner conductors 26and 28. In FIG. l the slidable element 22 is in its left position, andconnects the common conductor 24 to the branch conductor 26, While theother branch conductor 2 is isolated.r In

connects the common inner conductor 24 to the branch inner conductor 28,while the other branch inner conductor 26 is isolated.

An insulation rod 34 extendsthrough the aligned inner conductors 26 and2S and the slidable element 22. This rod 34 is secured to the slidableelement 22, but itis freely slidable in the stationary inner conductors26 and 2S. Thus the rod 34 may be used to move the element 22 betweenits left hand and right hand positions.

For this purpose the switch in the present case is provided with ahandle 36 which is operatively connected to the rod 34. Morespecifically, 'a part of therod has gear teeth to form a rack 3S. Asmall diameter gear 40 is housed in one of the branch inner conductors,in this case the conductor 2S, and meshes with the rack 38.` Aninsulation shaft 42 extends from the gear toy a point outside thevhousing for rotation by the handle 36.

Referring to FIG. l, handle 36 is connected through a shaft 44 to a gear46. This meshes with a pinion 4S operatively connected to the outer endof shaft 42. The `step-up gear ratio between gear` 46 and pinion 48 isso selected that the slidable element 22 is moved all the way to one orthe other branch conductor by a half turn of the handle 36. Moreover, inpreferred form the handle 36 is so mounted that it points in thedirection of one branch or the other, an`d specifically to that branchwhich has been connected or made operative. In FIG. l handle 36 pointsto the left, and slidable element 22 has beenl moved to the left. InFIG. 4 handle 36 points to the right, andv slidable element 22 has beenmoved to the right. 1W i. l,

The slidable element 22 is a hollow cylinder. It is made of a 'resilientconductive material, and in the present case it is made of heat `treatedberyllium copper, which preferably is vplated with a hard chromium-platefinish. The end portions 50 .and 52 are relatively thin walled andlongitudinally slotted to make the same resiliently yieldable. Thefparts30 and 32 of the stationary inner conductors constitute cylindricalseats which slidably receive the end 50 or S2 respectively. The ringzwslidably receives either end Sii or 52 of the slidable element. When,as in the present case, the midportion is'rigid or non-yieldable, it ispreferably somewhat `smaller in diameter'than the end portions 50 and52, so that it will readily slide through the ring 2i?. However theseats 30 and 32 'and the ring 26 are dimensioned lto receive the slottedparts of the element 22 with a snug lit which provides a good electricalcontact.

The rigid or non-slotted center portion of element 22 receives bushingswhich are internally dimensioned to re- Vceive theA insulation rod 34,and it -is secured thereto by means of ,transverse dowel pinsg56. v h

It will be observed that the ends of the slidable element are beveled tofacilitate entering theseats.v Of coursethe terhto Vthe hollowcylindrical ring 20. With the present i arrangement the slidable elementalways yields in compression, that iis, by contraction, instead of beingexpanded in one position and contracted in the other, as'

would be the case if the seats were received inside the slidableelement.l

The insulation shaft 42 preferably has ats at both ends. The flats 60 atthe outer end preferably are perpendicular to the flats 62 at the innerend, and these dats are received slidably between mating flats, andthereby serve to transmit torque to the shaft at thellats 60, and fromthe shaft to the rack gear 40 at the ats 62. This arrangement has theadvantage that the flats function somewhat as universal joints, andthereby accommodate any slight misalignrnent of the shaft.

Considering some features of the switch in greater detail, the handle 36may be a standard handle available for purchase in the commercialmarket. That here shown is made by Barkelew Electric Manufacturing Co.of Middletown, Ohio.

The handle has a depressible thumb button 64 which maybe depressedagainst a compression spring 66. It is connected to a lever 68 pivotedat 70, and the opposite end of which is connected to a lock pin 72. Theend of this may be received in either of two diametrically related holesin a cover plate 74, thus anchoring the handle in one end position orthe other.

The switch housing 12 as cast, preferably includes an integral platform76 on which the operating mechanism is mounted. This platform may besquare or rectangular in configuration, to provide mounting holes forthe switch, shown at 77 in FIG. 6. vIt receives a lower spacer 78 and amounting plate 80 (FIGS. l and 5) which may be circular in outline. Thegear 46 and pinion 48 are received between the platform 76 and themounting plate 80. The latter supports another and wider spacer 82, andthe cover plate 74, which again preferably are circular in outline. Thesuperposed parts 78, 80, 82, and 74 are secured together by appropriatescrews, but the section of FIG. 1 happens to pass through locatingdowels,

vof the switch.

Referring to FIG. 6, the shaft 44 carries an arm 84. This hasindependently adjustable stop screws 86 and 88. Screw 86 bears against`a iixed stop .90 when the switch is in the position shown in FIGS l and6,- and the screw 88 bears against a similar iixed stop 92'when the arm84 has been turned 180 degrees, or is in the position shown in FIG. 5.One end 94 of arm 84 is reduced in dimension and passes diametricallythrough a mating hole in shaft 44. It is keyed in position by a pin 916.

It is frequently desired to interlock the switch with other mechanism,and to indicate its position on appropriate pilot lamps or indicators,For this purpose the present switch carries four precision switches ors'o-called rnicroswitches. superposed at 98 and 100. On referring toFIG. 6, it will be'seen that there are another two such switches at 102,the lower switch" being concealed by the upper switch. Each switch hasan operating pin engaged by a feeler or tab, as is usual with suchswitches.

The Varm 84 has a pair of opposed, independently adjustable screws 104and 106. The head of the screw 106 is large enough to simultaneouslyengage the tabs of the superposed switches v98 and 100, and similarlythe head of screw 104 is large enough to simultaneously en- 'gage thetabs ofthe superposed switches at 102. It will be understood that thenumber of switches may be varied, dependingv on the needs in anyparticular case. The wiring from the switchesmay be led to a multiplepin detachable connector, the female-element of which is located inatting or holder 110, which is secured to the upper spacer 82 previouslyreferred to.

j nating in a female socket 166 (FIG. 1).

4 closed cylindrical portion 112. This is a matching stub, and isappropriately dimensioned for that purpose.

Inner conductor 26 is located within outer conductor 16 by insulationdiscsor so-called beads 114 and 116. These may be made of Teflon. Theyare received in mating annular channels in the inner conductor, and topermit assembly, the beads are slit as shown at 118, 120 in FIG. 7. Thematerial is flexible enough to permit opening of the split disc to bereceived over the necked portion of the inner conductor.

^ Similarly, the inner conductor 28 is supported by insulation beads 122and 124, and the inner conductor 24 is supported byinsulation beads 126and 128. In the case of conductor 24, it is important to orient the sameproperly so that the axis of ring 20 will remain'aligned with thebranches. For this purpose the outer periphery of bead 128 is keyed tothe housing at 130, and-inner conductor 24 is keyed to the bead 128 bymeans of adiametrical pin 132 (FIG. 1) received in a hole 129 (FIG. 7).

The inner conductor carries metal discs `134 and 136 which are brazed tothe inner conductor. They are matching rings to help match the impedanceof the common part 14, 24 to thefimpedance of a standard coaxial line.

It also is importantthat the inner conductor 28 be properly orientedwith respect to the branch 18, and for this purpose the bead 124 iskeyed at 140 to the inner conductor 28, and the periphery of the bead iskeyed at 142 to a ange plate 144 secured to flange 146 forming a part ofthe housing.

The particular switch here shown is for use with coaxial line orplumbing of large dimension, specifically standard 31/s inch coaxialline. The connections are standard E.I.A. tiange connections. The branch16 has an integral ange 150 which receives a body extension 152 havingnanges 154 and 156. This extension is employed because the innerstructure 26 terminates in a female socket 158, which is housed withinthe body.

At the end of the other branch the conductor 28 terminates in a male end160, or so-called bulletf This has longitudinal slots, as will be seenat 162 in FIG. 6. The bullet is somewhat resilient, but is made of brassinstead of beryllium copper like the slide `22, and it is reinforced byan internal helical spring 164 (FIG. 1). No body extension is used,because the b-ullet projects from the body.

The common inner conductor 24 is here shown termi- The body has a nange168 which receives the tlange170 of a body ex- In FIG. 1 there are twosuch switches 1 f tension 172 like the body extension 152. Thus thesocket 166 is housed within the body. It will be understood that eithera male bullet or a female socket may be provided at any of the threeports, as may be needed for any particular installation. Whenever afemale socket is provided the body extension is added. In this way onecast body serves for any combination of male and female connections.

Referring to FIG. 4, the slidable element 22 has an unslotted centerportion 200 which is somewhat thicker than the remainder of the element.This portion receives a pair of stepped bushings 202 having innerdiameter dimensioned to receive the insulation rod 34. The rod issecured in position by diametrical pins at S6. The end portions are slitas far as the middle portion 200, and a zone .at 204 adjacent thethickenedmiddle portion 200 is preferably thinned somewhat, therebyincreasing the yieldabil- 1ty of the end or contact .portions of theslidable element.

The diameter ofthe midportion 200 is somewhat less than that of the endportions, and this reduced diameter is Apreferably carried `throughjthezone 204 on each side of the midportion 200. y j

In the specific case here shown the slidable element 22 has 16 slots`uniformly distributed around its periphery, as shownin FIG. 3.Eachlslotis 0.032 inch wide.

The cylindrical ring 20 is longerjthan the depth of the seats 30 and 32.There is accordingly more surface cony, 30 db minimum.

tact at than at either 30 or 32. To maintain uniform electrical contact,the diameterot seats 3) and 32 is somewhat less than that'ofrthe ring20, so that there is somewhat greater contact` pressure where the areais less, thu compensating for the reduced contact area. Y

The rod 34 is made of insulation, preferably Teilen. The rack gear 40may be made of metal, preferably starnless steel. It has an adapter il(FIG. 2) with flats at 62 (FIG. l). 'I he insulation shaft 42 is made ofan insulation material of suicient strength. Pinion 48 (FIG. 1) isreceived on the' small end of a coupler, the larger end. of which has aflattened hole or socketwhich receives the flats 6@ of shaft 42. In theparticular switch here shown the gear ratio between gear 156 and pinion48 is six to one, so that a half revolution of handle -3d turns theinsulation shaft 4Z three revolutions. i0 is so selected that thesethree revolutions move the rack and the slidable elementtZZ all the wayfrom one end v positionV to the opposite end position.

The diameter of rack gear itl is preferably kept smallso This is shownin FG. 2,' in which the rack 33 and its driving gear 4@ are fully housedwithin the inner conductor 28. These parts have no significant eiectV onthe electrical elciency of the coaxial branch made up of inner`conductor 2h and outer conductor lid.

Most of the metal parts of theswitch are made of brass,

l and preferably are silver plated. However, the slidable ,for example,the Marmann quick disconnect flange.

The switchV was designed to operate overa frequency range of from 75.5to-985 mc. and to handle up to 1G kw.

Vaverage power;v .The VSWR was not to exceed 1.1 maximum; the insertion`loss'not to exceed 0.15 db maximum;

and the isolation between branches 16 and 13 was to be ln actualpractise the switch greatly exceeds these requirements, and it operatesefficiently over ltheentire `frequency range of the transmission line.The

isolation maybe increased by lengthening the switch. v

The diameter of rack gear thatis `is housed .fully within the innerconductor ZS.

The switch maybe used in a pressurized line.` Forthis will be seen'inthe drawing.

v The switch may be scaled down with appropriate modifications for linesof different size, for example 15/5 inch coaxial line.

It is believed that the construction and method of use, as well as theoperation and advantages of our improved switch, will be lapparent fromthe foregoing detailed description. lt will also be apparent that whilewe have purpose the anges are sealed by the use of O rings, as,

shown and described the invention in a preferred form, vchanges may bemade withoutdeparting from the scope of the invention, as sought to bedeined in the following "claims In the claims the reference totheslidable element ,being slidable through a ringf is not intended ltoexclude` an incomplete ring, or, any suitable passage extendingtransversely through the inner end of the common inner conductor. n

v1. Acoaxial switchcornprising a T-shaped housing providing the hollowouter conductors of a stem and two aligned branches, 'a commoninnerconductor through/the stem terminating at `its inner end in a ring whichis coaxial of the branches,` an inner conductor element passing throughand slidablein ,said ring on the commonaxis of said branches, a'stationary inner conductor in each branch, with itsl inner endterminating at a spacing from the common inner vconductor approximatingthe length of the slidable element,` whereby the latter may beused to lconnect said `common inner conductor to one orjthe other t to slide saidrod longitudinally.A

of the branch inner conductors, means at the end of the' stem forconnection to a coaxial conductor aligned with said stem, aligned' meansat the ends of the branches for connection to coaxial conductors alignedwith one another and with the branches, an insulation rod which isshorter than the combined length of the branches extending through bothof said'aligned inner conductors and through'said slidable element,saidrod being secured to said element but being slidable in both of saidstationary branch inner conductors, and means mounted on the side of oneof the branches operatively connected to said rod the slidable element,whereby the latter may be used to connect said common inner conductor toone or the other of the branch inner conductors, means at the endofnthestem for connection to a coaxial conductor` aligned with said stem,aligned means at the ends of the branches for connection to coaxialconductors aligned with one anotherV and with the branches, aninsulation rod which is shorter than the combined lengthof thebranchesfextending through both of said aligned inner conductors andthrough said slidable element, said `rod being secured to both of saidelements but being slidable in said stationary branch inner conductors,a part of said rod having gear teeth to form a rack, a gear in one ofthe branches and meshing with said rack, and means passing through thesideof the said branchto rotate said gear.

3, A Vcoaxial switch comprising a T-shaped housing providing the hollowouter conductors of a sternV and two valigned branches, a common innerconductor through the stem terminating at its'inner end in a ring whichis vcoaxial of the branches, an inner conductor element passing throughVand slidable in said ring, a stationary inner 'conductor in each branch,with its inner end terminating at a spacing from the common innerconductor-approximating the length of the slidable element, whereby thelatter may be used to connect said common inner conductor to one or theother of the branch innerV conductors, an insulation rod extendingthrough both ofV said aligned inner conductors and throughvsaid slidableelement, said rod being secured to said element butbeing slidable inboth of said stationary branch inner conductors, a part of said rodhaving gear teeth to form a rack,

a small diameter gear hcusedin one of the branch inner providing thehollow outer conductors of a stem and two Y aligned branches, a commoninner conductor through the i stem terminating at its inner end in aring which is coaxial of the branches, an inner conductor elementpassing through and slidable in said ring, a stationary inner conductorin each branch, with its inner end terminating at `aspacing from thecommon inner conductor approximating the length of the slidable element,whereby the latter may be used to connect said common inner conductor toone orthe other of thebranch inner'conductors, an in- V sulation rodextendingthrough said aligned inner conductors and slidable element,said` rod being secured to said element but being slidable in saidstationary branch inner conductors, apart of saidrrod ,having gear teethto forni" avrack, a small diameter gear housed in one of the branchinner conductors and meshing with said rack, said inner conductor' beingcylindrical and said gear being so small in diameter that it does notproject outside the cylindrical surface of said inner conductor, aninsulation shaft extending from said gear to a point outsidekthehousing, a handle manually rotatable for about one-half revolution topoint in the direction of one branch or the other, a gear turned by saidhandle, a pinion meshing with said gear and driving the aforesaidinsulation shaft, the stepup gear ratio being such that the slidableelement is moved all the way to one or the other branch inner conductorby a half turn of the handle and the handle acts as an indicator of theswitch position.

A coaxial switch comprising a T-shaped housing providing the hollowouter conductors of a stem and two aligned branches, a common innerconductor through the stem terminating at its inner end in a ring whichis coaxial of the branches, a single inner conductor element passingthrough and slidable in said ring, a stationary inner conductor in eachbranch, with its inner end terminating at a spacing from the commoninner conductor approximating the length of the slidable element,whereby theA latter may be used to connect said common inner conductorto one or the other of the branchinner conductors, a gear rack connectedto said slidable element,

,a very small diameter gear meshing with said rack, a

handle manually rotatable for about one-half revolution to point in thedirection of one branch or the other, a large diameter gear turned bysaid handle, a pinion meshing with said gear and driving the aforesaidrack gear, the step-up gear ratio being such that the slidable elementis `moved all the way to one or the other branch inner conductor by ahalf turn of the handle and the handle acts as l an indicator of theswitch position.

6. A coaxial switch comprising aT-shaped housing providing the hollowouter conductors of astem and two aligned branches, a common innerconductor through the stem terminating at its inner end in a ring whichis coaxial oi the branches, lan inner conductor element passing throughand slidable in said ring, a stationary inner conductorin each branch,with its inner end terminating at a spacing from the common innerconductor approximating the length of the slidable element, whereby thelatter may be used vto connect said common inner conductor to one or theother of the branch inner conductors, said slidable element being ahollow cylinder made of resilient conductive material, the end portions'of said cylinder being longitudinally slotted with a large number ofrelatively long slats to make the same resiliently yieldable, the innerends of the branch inner conductors terminating in cylindrical seats,said seats and the aforesaid cylindrical ring at the inner end of thecommon conductor being dimensioned to slidably receive the slottedl endportions of the slidable element with a snug tit for good electricalcontact. I

7, A coaxial providing the hollow outer conductors of a stem and twoaligned branches, va common inner conductor through the stem terminatingat its inner end in a ring which iscoaxial of the branches, an innerconductor element passing through and slidable in said ring, astationary inner conductor in each branch, with its innerfendterminating fat a spacing from the common inner conductor approximatingthe length of the slidable element, whereby the portion,v said endportions being longitudinally slotted with a large number of relativelylong slots to make the same'resiliently yieldablethe inner ends ofthebranch l inner conductors terminating incylindrical seats, said seatsand the aforesaid cylindrical ring at the inner end lof the commonconductor being dimensioned lto slidably receive the slotted ends of theslidable element'with a snug t for good electrical contact 'i 8. Acoaxial switch comprising a T-shaped housing providing the hollow outerconductors of a stem and two aligned branches, a common inner conductorthrough the stem terminating at its inner end in a ring which is coaxialof the branches, an inner conductor element passing through and slidablein said ring, a stationary inner conductor in each branch, with itsinner end terminating at a spacing from the common inner conductorapproximating the length of the slidable element, whereby the latter maybe used 'to connect said common inner conductor to one or the other ofthe branch inner conductors, said slidable element being a hollowcylinder made of heat treated beryllium copper, the end portions of saidcylinder being slightly greater in diameter than the mid portion, saidend portions being longitudinally slotted with a large number ofrelatively long slats to make the same resiliently yieldable, the slotsbeing long enough to pass through a part of the reduced diameter midportion to increase the yieldability of the end portions, the inner endsof the branch inner conductors terminating in hollow cylindrical seats,said seats and the aforesaid cylindrical ring at the inner end of thecommon conductor being dimensioned to slidably receive the slotted endsof the slidable element with a snug lit for good electrical contact.

9. A coaxial switch comprising a T-shaped housing providing the hollowouter conductors of a stem and two aligned branches, av common innerconductor through the stern terminating at its inner end in a ring whichis coaxial of the branches, an inner conductor element passing throughand slidable in said ring, a stationary inner conductor in each branch,with its inner end terminating at a spacing from the common innerconductor approximating the length ofthe slidable element, whereby thelatter may be used .to connect said common inner conductor to one or theother of the branch inner conductors,

an insulation rod extending through said aligned inner conductors andslidable element, said rod being secured to said element but beingslidable in said stationary branch inner conductors, means operativelyconnected to said rod to slide said rod longitudinally, said slidableelement being a hollow cylinder made of resilient conductive t material,the end portions of said cylinder being longituelement with a snug t forgood electrical contact.

switchicormprising a T-shaped housing branch, with its inner endterminating at a spacing from the common inner conductor approximatingthe length of the slidable element, whereby the latter may be used toconnect said common inner conductor to one or the other of the branchinner conductors, meanstat the end of the stemfor connection togacoaxial conductor aligned with said stem, aligned means at the ends ofthe branches for connection to coaxial conductors aligned with oneanother and with the branches, an insulation rod which is shorter thanthe combined length of the branches extendslidable in said stationarybranch inner-conductors, a part y of said rod having gear teeth to forma rack, a gear housed in one of the branches and meshing with said rack,means passing through the. side of said branch to rotate said gear, saidslidable element being a hollow cylinder made of resilient conductivematerial, the end portions of said cylinder being longitudinally slottedwith a large number of relatively long slots to make the sameresiliently yieldable, the inner ends of the branch inner conductorsterminating in cylindrical seats, said seats and the aforesaidcylindrical ring at the inner end of the cornmon conductor beingdimensioned to slidably receive the slotted end portions of the slidableelement With a snug t for good electrical contact.

11. A coaxial switch comprising a T-shaped housing providing the hollowouter conductors of a stern and two aligned branches, a common innerconductor through the stern terminating at its inner end in a ring whichis coaxial of the branches, an inner conductor element passing throughand slidable in said ring, a stationary inner conductor in each branch,with its inner end terminating at a spacing from the common innerconductor approximating the length of the slidable element, whereby thelatter may be used to connect said common inner conductor to one or theother of the branch inner conductors, an insulation rod extendingthrough said aligned inner conductors and slidable element, said rodbeing secured to said element but being slidable in said stationarybranch inner conductors, a part of said rod having gear teeth to form arack, a small diameter gear housed in one of the branchinner conductorsand meshing with said rack, said inner conductor being cylindrical andsaid gear being so small in diameter that it does not project outsidethe cylindrical surface of said inner conductor, an insulation shaftextending from said gear to a point outside the housing, a rotatablehandle, and means gearing said handle to the aforesaid insulation shaft,said slidable element being a hollow cylinder made of resilientconductive material, the end portions of said cylinder beinglongitudinally slotted to make the same resiliently yieldable, the innerends of the branch inner conductors terminating in cylindrical seats,said seats and the aforesaid cylindrical ring at the inner end of thecommon conductor being dimensioned to slidably receive the slottedelement with a snug t for good electrical contact.

l2. A coaxial switch comprising a T-shaped housing providing the hollowouter conductors of a stem and two aligned branches, a common innerconductor through the stem terminating at its inner end in a ring whichis coaxial of the branches, an inner conductor element passing throughand slidable in said ring, a stationary inner conductor in each branch,with its inner end terminating at a spacing from the common innerconductor approximating the length of the slidable element, whereby thelatter may be used to connect said common inner conductor to one or theother of the branch inner conductors, an insulation rod extendingthrough said aligned inner conductors and slidable element, said rodbeing secured to said element but being slidable in said stationarybranch inner conductors, a part of said rod having gear teeth to form arack, a small diameter gear housed in one of the branch inner conductorsand meshing with said rack, said inner conductor being cylindrical andsaid gear being so small in diameter that it does not project outsidethe cylindrical surface of said inner conductor, an insulation shaftextending from said gear to a point outside the housing, a handlemanually rotatable for about one-half revolution to point in thedirect-ion of one branch or the other, a gear turned bysaid handle, apinion meshing with said gear and driving the aforesaid insulationshaft, the step-up gear ratio being such that the slidable element ismoved all the Way to one or the other branch inner conductor by a halfturn of the handle, said slidable element being a hollow cylinder madeof resilient conduc tive material, the end portions of said cylinderbeing longitudinally slotted to make the same resiliently yieldable, theinner ends of the branch inner conductors terminating in cylindricalseats, said seats and the aforesaid cylindrical ring at the inner end ofthe common conductor being dimensioned to slidably` receive the slottedelement with a snug lit for good electrical contact.

13. A coaxial switch as defined in claim 2 in which the means extendingoutward from the rack gear is an insulation shaft which has ilats atboth ends, the ats at one end being perpendicular to the iiats at theother end, said flats being received between mating flats and therebyserving to transmit driving torque to the shaftand from the shaft to therack gear, said ats functioning somewhat as universal joints.

14. A coaxial switch as dened in claim 3 in which the insulation shaftextending outward from the rack gear has flats at both ends, the ats atone end being perpendicular to the tlats at the other end, said flatsbeing received between mating flats and thereby serving to transmitdriving torque to the shaft and from the shaft to the rack gear, saidats functioning somewhat as universal joints at the ends of saidinsulation shaft and thereby accommodating any slight misalignment ofthe shaft.

15. A coaxial switch as delined in claim 4 in which the insulation shaftextending outward from the rack gear has iiats at both ends, the flatsat one end being perpendicular to the flats at the other end, said flatsbeing received be tween mating ats and thereby serving to transmitdriving torque to the shaft and from the shaft to the rack gear.

16. A coaxial switch as deiined in claim 10 in which the means extendingoutward from the rack gearVV is an insulation shaft which has Hats atboth ends, the flats at one end being perpendicular to the flats at theother end,

said flats being received between mating ats and thereby serving totransmit driving torque to the shaft and from thershaft to the rackgear.

17. A coaxial switch as dened in claim 11 in which the insulation shaftextending outward from the rack gear has ats at both ends, the ats atone end being perpendicular to the llats at the other end, said flatsbeing received between mating flats and thereby serving to transmitdriving torque to the shaft and from the shaft to the rack gear, saidflats functioning somewhat as universal joints at the ends of saidinsulation shaft and thereby accommodating any slight misalignment ofthe shaft.

18. A coaxial switch as deiined in claim 12 in which the insulationshaft extending outward from the rack gear has Hats at both ends, theiiats at one end being perpendicular to the iiats at the other end, saidflats being received between mating flats and thereby serving totransmit driving torque to the shaft and from the shaft to the rackgear.

References Cited in the file of this patent UNITED STATES PATENTS2,637,787 Price May 5, 1953 2,794,087 Jennings et al. May 28, 19572,949,586 Holzschuh et al. Aug. 16, 1960

1. A COAXIAL SWITCH COMPRISING A T-SHAPED HOUSING PROVIDING THE HOLLOWOUTER CONDUCTORS OF A STEM AND TWO ALIGNED BRANCHES, A COMMON INNERCONDUCTOR THROUGH THE STEM TERMINATING AT ITS INNER END IN A RING WHICHIS COAXIAL OF THE BRANCHES, AN INNER CONDUCTOR ELEMENT PASSING THROUGHAND SLIDABLE IN SAID RING ON THE COMMON AXIS OF SAID BRANCHES, ASTATIONARY INNER CONDUCTOR IN EACH BRANCH, WITH ITS INNER ENDTERMINATING AT A SPACING FROM THE COMMON INNER CONDUCTOR APPROXIMATINGTHE LENGTH OF THE SLIDABLE ELEMENT, WHEREBY THE LATTER MAY BE USED TOCONNECT SAID COMMON INNER CONDUCTOR TO ONE OR THE OTHER OF THE BRANCHINNER CONDUCTORS, MEANS AT THE END OF THE STEM FOR CONNECTION TO ACOAXIAL CONDUCTOR ALIGNED WITH SAID STEM, ALIGNED MEANS AT THE ENDS OFTHE BRANCHES FOR CONNECTION TO COAXIAL CONDUCTORS ALIGNED WITH ONEANOTHER AND WITH THE BRANCHES, AN INSULATION ROD WHICH IS SHORTER THANTHE COMBINED LENGTH OF THE BRANCHES EXTENDING THROUGH BOTH OF SAIDALIGNED INNER CONDUCTORS AND THROUGH SAID SLIDABLE ELEMENT, SAID RODBEING SECURED TO SAID ELEMENT BUT BEING SLIDABLE IN BOTH OF SAIDSTATIONARY BRANCH INNER CONDUCTORS, AND MEANS MOUNTED ON THE SIDE OF ONEOF THE BRANCHES OPERATIVELY CONNECTED TO SAID ROD TO SLIDE SAID RODLONGITUDINALLY.